chore: test travis env tools

Author: KingDarBoja

tox.ini

@@ -1,8 +1,13 @@
 [tox]
 envlist = 
-    black,flake8,import-order,mypy,manifest,py{27,35,36,37,38,39-dev,py,py3}
+    black,flake8,import-order,mypy,manifest,
+    py{27,35,36,37,38,39-dev,py,py3}
 ; requires = tox-conda
 
+[travis]
+python =
+    3.6: py36,black,flake8,import-order,mypy
+
 [testenv]
 passenv = *
 setenv =
@@ -16,31 +21,31 @@ commands =
     pytest --cov-report=term-missing --cov=graphql_server tests {posargs}
 
 [testenv:black]
-basepython=python3.7
+basepython=python3.6
 deps = -e.[dev]
 commands =
     black --check graphql_server tests
 
 [testenv:flake8]
-basepython=python3.7
+basepython=python3.6
 deps = -e.[dev]
 commands =
     flake8 setup.py graphql_server tests
 
 [testenv:import-order]
-basepython=python3.7
+basepython=python3.6
 deps = -e.[dev]
 commands =
     isort -rc graphql_server/ tests/
 
 [testenv:mypy]
-basepython=python3.7
+basepython=python3.6
 deps = -e.[dev]
 commands =
     mypy graphql_server tests --ignore-missing-imports
 
 [testenv:manifest]
-basepython = python3.7
+basepython = python3.6
 deps = -e.[dev]
 commands =
     check-manifest -v